The present invention relates to a storage assembly for storing imbricated or overlapped copies of printed and folded material upon a pallet. Within the field of printing it is common to temporarily store pro-printed material for later assembly with other printed materials. In the past, this was done by stacking individual printed copies, one on top of another, and placing these vertical stacks upon a pallet. In some cases, partial vertical stacks were tied together to form bundles which were subsequently placed upon pallets. In recent times, the printing industry has recognized that this form of storage is inefficient because it requires a machine to remove individual copies within an imbricated formation upon a conveyor belt and place them one on top of the other in a vertical stack. Conversely, when the stored materials are retrieved, they must be taken from a vertical stack and reformed into an imbricated form upon a conveyor. The machines for doing this type of storage and retrieval are complicated, subject to malfunction, and are relatively slow.
One attempt at solving the problem of inefficient storage and retrieval of an imbricated copy stream has been widely adopted by the printing industry. This solution involves storing the individual printed copies within their imbricated formation directly upon large storage spools using a reel for winding the copies upon the spool. As the copy stream moves down the conveyor, the imbricated formation is placed upon a strip of continuous separating tape that is subsequently wound tightly upon large spools. A full spool of stored printed copies is cylindrical in shape and stores a single row of an imbricated copy stream. This technology was primarily developed and marketed by a European corporation, Ferag.
Although Ferag's reeling machines solve the problem of inefficient storage and retrieval by maintaining the imbricated formation during storage and retrieval, there are other disadvantages that arise in using Ferag's approach to the problem. First, the storage spools do not use storage space efficiently. The most efficient shape for storing materials is a cubic-shape, and the most common form to achieve the cubic-shape is upon a rectangular pallet. Cylindrical spools inherently waste storage space. Additionally, the cylindrical spools waste space at their respective centers. A second disadvantage of Ferag's machines is that cylindrical spools are inherently more difficult to handle. Pallets are the most common form of storage, and forklifts and other machines are built to handle rectangular pallets. Handling of cylindrical spools require special equipment that is more expensive and more complicated to maintain and operate. A third disadvantage is that the copy stream is stored on a curved path that temporarily deforms the normally flat printed copies. This makes handling the partially deformed copies more difficult, upon retrieval. A fourth disadvantage is that when handling and storing newspapers upon a spool, every other individual newspaper must be turned 180.degree. prior to storing the newspapers. This is because the secondary folds of each newspaper make the newspaper thicker at one side, and the newspapers must be alternated to keep the spool balanced in width.
Another alternative approach to vertical stacking of printed copies was developed by the Harris Corporation (now Harris Graphics, Inc.). Harris used special trays to form substantially horizontal stacks of newspapers, signatures, and other types of printed material. As the imbricated copy stream exits the conveyor, the copy stream is compressed upon an elongated tray such that the individual copies are standing almost vertically on end. Individual trays can subsequently be stacked, one on top of the other upon a pallet. The Harris tray approach has not been found to be commercially viable within the printing industry. Although this approach allows the use of cubic-shaped storage units upon pallets, in contrast to Ferag's storage method, it still does not resolve the basic problem of inefficient destroying and reforming of the imbricated copy stream during storage and retrieval, respectively. Additionally, there are several other disadvantages associated with the use of Harris' storage method. First, this method requires specially formed trays that would be expensive. Second, some storage space is wasted between the top edge of the horizontal stack and the bottom of the next tray. Third, horizontal stacking of printed materials may deform the edges of individual printed copies. Fourth, the relatively narrow and long trays would be relatively unstable when stacked upon one another in a pallet arrangement.
In addition to the problems associated with the use of the machines developed by Ferag and Harris, noted above. There are common problems associated with all prior art storage methods and machines. First, all of them are relatively slow in the total time that it takes to store and retrieve the printed copies from and to a conveyor. Even the amount of time that it takes to store and retrieve the copies with the Ferag method can be improved upon. Second, all of the prior art storage methods use a single row storage method. Efficiency in time and storage space may be improved with the use of a multiple row storage system. Finally, none of the prior art methods use a relatively flat and linear imbricated form for storing a printed copy stream. The relatively flat lay of the copy stream is the most stable way to store the individual copies, and allows the stack to remain stable even if the individual copies are unsymmetrical in size and/or shape. The prior art stacks and machines are not efficient in storing such unsymmetrical articles.